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Emerging nanomaterials such as nanozymes have recently been applied for the immunoassay-based detection of biomarkers. However, the inferior catalytic activity and low water solubility of nanozymes remain as the major limitations compared to natural enzymes. To overcome these limitations, we successfully synthesized a superior nanozyme with a structure of enriched 2D catalytic interface, namely Nanozyme Nest, which was composed of Fe-based metal–organic frameworks (Fe-MOF) and graphene oxide (GO). Then, we applied it in an ultrasensitive enzyme-linked immunosorbent assay (ELISA) for the detection of benzo­[a]­pyrene-7,8-diol 9,10-epoxide–DNA adduct (BPDE–DNA), which is a metabolite of benzo­[a]­pyrene (BP) and used as a typical biomarker of woodsmoke exposure in human blood. The Nanozyme Nest features amplified peroxidase-like catalytic ability from graphene and Fe-MOF due to their large surface area and abundant active sites. By using the proposed Nanozyme Nest-based ultrasensitive ELISA, the BPDE–DNA could be detected at a level as low as 0.268 ng/mL, and the obtained sensitivity was much higher than most of the widely used methods. Our work provides a novel strategy to design ultrasensitive immunosensors with advantages of amplified catalytic activity and improved water solubility compared to classic nanozymes. This illustrates the promising applications of the Nanozyme Nest-based immunosensors in point-of-care settings to conveniently detect exposures and diagnose diseases.

Because human immunodeficiency virus (HIV) has been one of the most terrible viruses in recent decades, early diagnosis of the HIV gene is of great importance for all scientists around the world. In our work, we developed a novel electrochemical biosensor based on one-step ultrasonic synthesized graphene stabilized gold nanocluster (GR/AuNC) modified glassy carbon electrode (GCE) with an exonuclease III (Exo III)-assisted target recycling amplification strategy for the detection of HIV DNA. It is the first time that GR/AuNCs have been used as biosensor platform and aptamer with cytosine-rich base set as capture probe to construct the biosensor. With the combination of cytosine-rich capture probe, good conductivity and high surfaces of GR/AuNCs, and Exo III-assisted target recycling amplification, we realized high sensitivity and good selectivity detection of target HIV DNA with a detection limit of 30 aM (S/N = 3). Furthermore, the proposed biosensor has a promising potential application for target detection in human serum analysis.

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The progress of additive manufacturing (AM), known as 3D‐printing, has initiated a revolution in the new generation of biosensors and bioanalytical devices in recent years. The advancement in the resolution of AM has enabled the microfabrication of the architectures of electrodes and sensing layers for high‐performance sensing. Diversiform printable materials, including biocompatible materials, polymers, various gels and metals, have enormously broadened the horizon in sensors and analytical devices for both research and commercial purposes. The considerable shortening of time and cost in sensor prototyping and fabrication has been reported and various highly customizable biosensing platforms and devices are under development. Herein, the most recent studies on the applications of AM in biosensors and bioanalytical devices are summarized with the aim to provide a panorama of emerging 3D‐printing strategies for sensor design and bioanalytical device fabrication.